Method of treating ores



FREDERICK VI. 'WUUD, JF BiliLTIIdUE/E, MARYLAND.

MEITHUD U'j ULREJMIING' ORES.

ld'llddlfilfill.

No Drawing. Application filed June specification of Letters l'ratcnt.

lPatented Mar. 30, 1920.

M, 191%, serial No. $463M. Renewed July 28, 1919. Serial No.

To all whom it 772/641] concern:

lle it known that l, l rmonnron W. VVooo, ot the United States, resldmg at "o, in

the State of Maryland, have my C l in new and useful improveim ll uiti in .lil ethods ot 'lreating tires, of which the following is a specification.

'lhis invention relates to a method of treating plastic ores, more particularly iron ores, to enable the same to be economically and practicably handled and smelted.

In a certain locality, large deposits of ore occur, consisting of hydrated sesquioxid of iron, intimately mixed with alumina and silica, the alumina being in excess of 8%, also small portions. of other mineral substances, all of these constituents being in a state of extreme subdivision. The undisturbed ore is of the consisten-c oi firm 01a and contains in addition to the above sub stances, a large proportion oi absorbed or hygroscopic water, the average percentage being approximately 24% to 528%. Owing to the fact that when dry, the ore becomes mainly an exceedingly fine powder, which in the blast furnace is carried away by the rapidly moving currents of gas, it has not been feasible to smelt the ore in the furnace in its natural state, and resort has been had to preliminary treatment of the ore in rotary kilns at a suiiiciently high temperature to cause incipient fusion or sintering, thereby causing the line particles to agglomerate into nodules or pellets. It has been feasible, with the ore in this agglomerated form to successfully subject it in the blast furnace to the usual and ordinary process of smelting generally employed in the manutacture of pig iron. To avoid the expense, incident to the nodulizing process, for fuel and manipulation, attempts have been made to form the ore in its natural condition, as mined, into briquets or other compact bodies oi sufiicient strength to withstand the nec essary handling, and of sufiicient size to resist the lifting influence of the upward currents of gases in the blast furnace. But these attempts have not been entirely successful, because of the strong adhesion oi? the plastic mass to the surfaces of the dies, molds, rolls and other molding devices; the tenacity with which the mined ore retains the absorbed water, even after the ore is exposed to the air, causing the material to retainits plastic clay-like conditmn for a considerable period. Further, owing to the high percentage of absorbed water contained in the ore in its natural state, such bricks or briqucts as can be made, have not been found strong enough they come from the molds, to withstand the handling and abrasion in the several operations. of charging the furnace and smelting, without excessive breakage and the formation of fine material.

I have found by a series of experiments, that if the amount of absorbed or hygroscopic wat n the ore is adjusted to a certain, point, eii by adding water to bring the amount up to the desired point, or by partially drying the ore to reduce the amountto the desired point, there will not be such tendency of the ore to adhere to metal surfaces as will prevent the ore from being formed by means of suitable compressing or molding apparatus into briquets or like bodies oi sui'hcient strength to withstand subsequent handling in charging into the blast furnace, and the operation oi? smelting, with very small, if any, loss in dust. The amount of hygroscopic water which I have i'ound that the ore may possess in order to be handled in this manner, from between l l u and 20%, and my invention therefore comprehenc method of treatment of the ore, consisting in adjusting its. content of hygroscopic or combined water to between l-l% and 20% or thereabout. In its more specific aspect my invention consists of a method of treatment of the ore. in which the ore is partially dried to reduce its content of hygroscopic water; and lurthem my invention consists in a method of treatment consisting in adjusting the con tent of hygroscopic water to the aroper amount, and then compressing or molding the treated ore under heavy pressure in the form 01 bricks, briquets and like bodies.

In treating plastic ore which contains substai'itially the amount of hygroscopic water occurring in the natural condition of the ore, and. as it is mined, that is approximately between 2-t% and 28%, in order to enable the ore to be compressed or molded into briquets and the like, 1 subject a quantity of the ore to a partial drying action in any suitable manner and by the aid of suitable and appropriate apparatus, and by this means I reduce the water content of the ore until it contains from 14% to 20%, preterably 18% of hygroscopic water. In this condition, and While still plastic, the amount of hygroscopic Water is not sulficient to cause the ,ore to adhere stron ly to the metal surfaces of rolls, dies, molds or like forming or compressing apparatus, the result being that the treated ore can be readily formed or molded under heavy pressure into bricks, briquets or like bodies of sufficient size and strength to adapt them to be subsequently handled incharging-into the blast furnace, and in the smeltingoperation. If from any cause the amount of hygroscopic Water has been reduced below 14% say, I bring the total hygroscopic content up to the desired point, by adding sufiicient Water thereto, and in this manner adjust the content to the proper poin t f'or enabling the ore to be successfully compressed or molded into b1"- 20.

quets.

The treated ore in its plastic condition containing. the proper amount of hygro seopic water may be formed or molded into briquets or similar bodies by suitable compressing apparatus which in itself forms no part of the present invention, and therefore will not be herein described.

- The briquets as discharged from the molding cavities, While still damp, possess a degree of toughness which renders them less liable to br akage and the formation of fine dust in handling, than if the hygroscopic Water is more completely removed.

y charging the briquets in the damp condition intothe smelting furnace, they have time to-descend therein and become covered by the successive layers of fuel, flux and ore, before becoming dry. Consequently, the liability of the removal of fine particles inthe-forln of dust from their surfaces, by the. contactwith the other materials making up the charge is reduced.

Having thus described my invention, what I claim is: A

1. The method of treating plastic ore containing in its natural state hygroscopic water, preparatory .to compressing the same into briquets and like bodies, which consists. in adjusting the content of hygroscopic and 20% or there- Water to between 14% about to prevent the ore from adhering strongly to the compressing surfaces.

2. The method of treating plastic ore containing in its natural state hygroscopic water, preparatory to forming said ore into briquets, Which method consists in subjecting the ore to a drying action to reduce its content of hygroscopic water sullicieutly to prevent the ore from adhering strongly to the briqucting surfaces.

3. The method of treating plastic ore containing in its natural state a large proportion of hygroscopic water, preliminary to forming said ore into briquets and like bodies, Which method consists in subjecting the ore to a drying action to reduce said content of hygroscopic Water sulliciently to prevent the ore from adhering strongly to the forming surfaces.

4. The method of treating plastic ore containing in its natural state hygroscopic Water in the proportion of from 21% to 28% or thereabout, which consists in subjecting said ore to a drying action suflicient to reduce its content of hygroscopic water to from 14% to 20% or thereabout to facilitate the subsequent handling of the ore.

5. The method of treating plastic ore containing in its natu 'al state hygroscopic Water, which consists in subjecting said ore to a drying action to reduce its content of hygroscopic Water sulficiently to facilitate the subsequent briqueting of the ore, and then forming said treated ore into briqucts or like bodies.

6. The method of treating plastic ore containing in its natural state hygroscopic Water in the proportion of from 21% to 28% or thereabout, which consists in subjecting said ore to a drying action sullicicut to reduce its content of hygroscopic water to from 1 1% to 20% or thereabout, and then forming said treated ore into briquets or like bodies.

7. The method of treating taining 8% or more of alumina, which consists in adjusting the hygroscopic Water content to between 14% and 20%, subjecting the treated ore to heavy pressure to form the same into briquets and like bodies, and charging said briquets into a smelting furnace.

In testimony whereof I have allixed my signature in presence of two Witnesses.

FREDERICK W. WOOD.

plastic ore conllitnesses A. G. BUTLER, H. I. NEWLIN. 

